The purpose of this project is to develop improved drug therapies for nervous system disease. Towards this end investigations seek to determine the relationship between dysfunction in a specific neurotransmitter system and the appearance of a particular neurologic syndrome. In addition, the ability of novel pharmacologic agents to modify the activity of specific transmitter systems in brain and spinal cord are investigated. Major topics under current study include: 1) Use of a stable isotope of oxygen to evaluate central monoamine metabolism in man. 2) Relation of monoamine- and peptide-containing neural system activity to specific motor, sensory, behavioral, or endocrinologic functions. 3) Ability of selective agonists and antagonists of receptors in systems mediated by dopamine, serotonin, acetylcholine, or gamma aminobutyric acid to influence neurologic function.